What Hardware Is Required?
Since you require 2,800 IP phones and 8,284 device units, under Cisco recommendations
you would need four CallManager servers which could support up
to 5,000 phones.This combination would allow for further growth, as well as
improved performance and reliability.
You should suggest using four Cisco MCS-7835-1000, PIII 1000MHz, with
1 GB RAM.This would allow for a maximum of 10,000 IP phones, and 20,000
device units. If cost were a primary issue, lower specification servers could be
used instead to achieve your design goals.